Abstarct: This research studies the static and dynamic analysis of the cantilever microbeam under electrostatic stimulation, piezoelectric and magnetic field. The microbeam is considered as a Euler-Bernoulli beam and a piezoelectric laxyer is placed on it. Also, the free end this microbeam is attached to the magnetorheological elastomer laxyer and a constant magnetic field is applied to it. Equations of motion and boundary conditions have been extracted by the Hamilton principle. The effect of magnetic stimulation of the elastomer laxyer as a dirac delta function enters into the equations of motion. Then, the motion equations are solved using a combination of the Galerkin method and Perturbation technique. In this thesis, static deformation, pull-in voltage, natural frequency and dynamic response are studied using two methods of modeling. In the first modeling, the magnetorheological elastomer laxyer in the free end is connected to the microbeam in the shear mode and in the second modeling in the compression mode.